Semiconductor device fabrication is utilized to form integrated circuitry (IC), micro-electro-mechanical systems (MEMS), and other micro-structures and assemblies.
The fabrication of an IC may involve implanting dopant into a semiconductor substrate, followed by activation of the dopant.
The implanting may comprise directing energized atoms or molecules of dopant at a semiconductor substrate to drive the dopant to a desired depth within the substrate, and may damage the substrate. For instance, if the dopant is driven into a monocrystalline silicon substrate, some regions of the substrate may become amorphous due to interaction of such regions with the energized atoms or molecules of the dopant.
The amorphous regions are defects, and may disrupt operation of integrated circuit components. Accordingly, it is desired to recrystallize the amorphous regions. Thermal energy has been used to recrystallize amorphous regions. However, many materials utilized in IC are not stable to the thermal energy utilized for recrystallization of silicon. If such materials are present, thermal energy cannot be used for recrystallization of the amorphous silicon without taking a risk of damage to the thermally unstable materials. It is therefore desired to develop new methods for recrystallizing amorphous regions.
Amorphous regions may occur through other mechanisms besides as defects induced during a dopant implant, and may be problematic in other structures besides integrated circuits. For instance, amorphous regions may be problematic in MEMS, and accordingly it would be desired to develop methods that may be applied to diverse applications of semiconductor device fabrication, including, but not limited to MEMs fabrication and IC fabrication.
Some improved methods have been developed for recrystallization of amorphous regions, with such improved methods comprising exposure of a semiconductor construction to radiofrequency radiation or to microwave radiation. However, even the improved methods may lead to undesired heating of semiconductor constructions, and accordingly it would be desired to develop new methods for recrystallization of amorphous regions.
As mentioned above, dopant is activated after it is implanted into a semiconductor substrate. The activation of the dopant comprises transferring the dopant from interstitial positions adjacent a lattice structure of a semiconductor material, into lattice sites of the lattice structure. Dopant activation is traditionally done utilizing thermal energy, but such may lead to the same problems that were described previously as being associated with the utilization of thermal energy for recrystallization of amorphous material. There has been some effort to utilize radiofrequency radiation or microwave radiation for dopant activation, but such may still lead to undesired heating of the semiconductor construction. It is therefore desired to develop methods for activating dopant which avoid undesired heating of semiconductor constructions.